Abrading device

ABSTRACT

An abrading device including at least two elongated abrading members and a mounting means for connecting the members to a rotating drive means, which rotates the mounting means and thus the abrading members to accomplish abrading. The mounting means supports each abrading member at a position offset from the axis of rotation of the mounting means for pivotal movement about an axis which is perpendicular to a plane forming a positive subtended angle of less than 90* with a plane perpendicular to the axis of rotation. During rotation, the abrading edges of the abrading members define a conical surface.

United States Patent [191 Whitsett [4 Oct. 21, 1975 ABRADING DEVICE 21 Appl. No.: 538,578

Related US. Application Data [63] Continuation-in-part of Ser. No. 395,971, Sept. 10,

1973, Pat. No. 3,858,367.

[52] US. Cl 51/332; 15/236 HO; 30/172;

. 29/81; 125/5 [51] Int. Cl. B24B 9/02; B23D 79/08 [58] Field of Search 125/5, 3; 29/81; 51/179,

[56] References Cited UNITED STATES PATENTS 3,065,579 11/1962 Clark 51/331 3,662,424 5/1972 Whitsettm. 15/236 HO 3,790,983 2/1974 Whitsett 15/236 B FOREIGN PATENTS OR APPLICATIONS 368,580 2/1939 Italy 51/332 Primary Examiner-0the1l Ml. Simpson Attorney, Agent, or FirmRoylance, Abrams, Berdo & Kaul [57] ABSTRACT An abrading device including at least two elongated abrading members and a mounting means for connecting the members to a rotating drive means, which rotates the mounting means and thusthe abrading members to accomplish abrading. The mounting means supports each abrading member at a position offset from the axis of rotation of the mounting means for pivotal movement about an axis which is perpendicular to a plane forming a positive subtended angle of less than 90 with a plane perpendicular to the axis of rotation. During rotation, the abrading edges of the abrading members define a conical surface.

7 Claims, 8 Drawing Figures U.S. Patent Oct. 21, 1975 Sheetlof2 3,913,282

FIG. I

ABRADING DEVICE This application is a continuation-in-part of my copending U.S. application Ser. No. 395,971, for Abrading Device, filed Sept. 10, l973, now U.S. Pat. No. 3,858,367.

The present invention relates to an abrading device and, more particularly, it relates to a device having at least two or more abrading members which are rotated by suitable means, such as an electric drill.

The device is to be used to abrade surfaces, thereby removing some type of surface coating therefrom. These coatings may be paint, rust, scale, marine growth, or wallpaper. Additionally, the device is to be used tofmish concrete surfaces by abrading from the concrete various imperfections and inconsistencies raised from the surfaces.

The abrading device disclosed in the aforementioned U.S. application, of which the present invention is an improvement, supports a plurality of abrading members .at a position which is offset from the axis of rotation of the mounting assembly and also supports these abrading members so that the edges of the rotating members define a conical surface during rotation. This is accomplished by positioning the mounting apertures in each abrading member in the required relationship relative to the centroid of the abrading members. Thus, centrifugal force tends to keep these abrading members in the dynamic conical surface forming position. Accordingly, when the edges of the abrading members are forced against a surface to be abraded, these members are forced out of the dynamic position, yet tend to return to this dynamic position. This results in an added force being applied to the abrading members, and thus to the surface to be abraded. This enhances the abrading action by providing a chipping action due to the oscillation of the abrading members caused by hitting high points on the surface to be abraded and being pushed upwards.

Finally, the device disclosed in the aforementioned U.S. application supports the abrading members in a position which is substantially perpendicular to the surface to be abraded.

The device of the present invention also supports the abrading members offset from the axis of rotation of the mounting means and also positions these members so that the edges describe a conical surface during rotation. However, in the present invention the abrading members can be generally characterized as being positionedat an angle of less than 90 relative to the surface which is to abraded.

More specifically, in, the present invention the axis about which each abrading member pivots is perpendicular to a plane which forms a positive subtended angle of less than 90 with a plane perpendicular to the axis of rotation of the mounting means upon which the abrading members are supported, thus confronting a plane abrading surface at less than 90.

Such a positioning of the abrading members provides three specific advantages of the present invention over that described in the aforementioned U.S. application. For one thing, there is less of a bending stress on the means supporting each abrading member because this means is at an angle which is less than 90 to the plane perpendicular to the axis of rotation of the entire device. For another thing, the abrading members, because of the angle in which they are supported, tend to unwanted materials away from the rotating abrading members. For a third thing, the chipping action of the abrading members is increased because the abrading member contacts the surface to be abraded at a lower angle of incidence.

Moreover, since the abrading edge of the abrading member strikes the surface to be abraded at less of an angle, the edge is essentially sharpened due to this contact, thereby increasing the abrading action thereof.

It is therefore an object of the present invention to provide a new and improved abrading device.

Another object of the present invention is to provide an abrading device which can. be used with a conventional rotating power supply, such as an electric drill, so that the abrading device can be made available at reasonable cost to the average homeowner.

Another object of the present invention is to provide a simple form of abrading device which is adaptable and versatile, yet which can be used with a minimum amount of manual effort.

A further object is to provide an abrading device of increased abrading efficiency.

The foregoing objects are attained by providing in combination with a rotating drive means at least two axially elongated abrading members, each comprising a blade portion having a first end, a second end, a top edge and an abrading edge, and having mounting apertures, each aperture located in one of the blade portions between the first end and the mid-point between the first and second ends; mounting means, rigidly connected to and rotatable by the rotating drive means, for supporting the abrading members, said mounting means including means for freely supporting the abrading members for pivital movement about fixed axes at a position offset from the axis of rotation of the mounting means, the mounting means having an axis of rotation coaxial with the axis of rotation of the drive means, the means for freely supporting the abrading members including rods secured to the mounting means along the axes, each of the axes being perpendicular to a plane which forms a positive subtended angle of less than with a plane perpendicular to the axis of rotation, the mounting apertures each having a diameter larger than the rods and each of the rods passing through one of the apertures, the means for freely supporting the abrading members also supporting the abrading edges in non-coplanar planes when the drive means is not rotating, the edges forming dihedral angles of less than with a plane perpendicular to the axis of rotation, the means for freely supporting the abrading members also supporting the abrading edges at an angle to the plane perpendicular to the axis of rotation which is greater than the dihedral angles when the rotating drive means is operated so the abrading edges describe a conical surface, the device being operative to accomplish abrading by engaging at least a portion of the abrading edges against an object as the abrading members rotate to thus cause the abrading edges to abrade the object.

Other objects, advantages and salient features of the present invention will be come apparent from the following detailed description which, taken in conjunction with the annexed drawings, discloses a preferred embodiment thereof.

Referring now to the drawings which form a part of this original disclosure;

FIG. 1 is a side elevational view of the device in accordance with the present invention in operation;

FIG. 2 is a top plan sectional view of the device in accordance with the present invention taken along lines 2-2 in FIG. 1;

FIG. 3 is a side elevational view of the device without the drive means coupled thereto and with the abrading members in their rest position;

FIG. 4 is a prospective view of one of the abrading members;

FIG. 5 is a side elevational sectional view taken along lines 55 in FIG. 2;

FIG. 6 is a fragmentary side elevational view showing an abrading member oriented at FIG. 7 is a fragmentary side elevational view of an abrading member oriented at 45;

FIG. 8 is a prospective view of an abrading member which is slightly curved along its length.

Referring now to the drawings in further detail, a typical form of the abrading device is shown in FIG. 1 and is generally designated 10. The abrading device includes a plurality of abrading members generally designated 12 and a mounting means generally designated 14.

The mounting means 14 comprises a cylindrical body 16, a connecting element 18 and a plurality of U- shaped guide elements 20. These guide elements extend outwardly from the cylindrical body 16 and are spaced around the body at 90 intervals. As best seen in FIGS. 2 and 3, each U-shaped guide element is formed from two substantially rectangular, elongated bars 22 and 24, each of which is rigidlycoupled or integral with, the cylindrical body 16. Along most of their lengths, a slot 26 is defined between the two bars 22 and 24 for the reception of the abrading members 12, to be described in more detail hereinafter. Each slot 26 is substantially rectangular in cross-section.

As seen in FIG. 2, formed in the bars 22 and 24, at the same distance away from the cylindrical body 16, are two apertures 28 and 30.

As best seen in FIGS. 1-3, the slot 26 is at an angle less than 90 to the plane A which is perpendicular to the axis of rotation B of the mounting means 14.

Referring now to FIG. 4, one of the abrading members 12 is shown therein to be in the form of an elongated rectangular bar having a first end 38, a second end 40, a top edge 42 and an abrading edge 44. The first and second ends are opposite each other, as are the top and abrading edges. Formed in the bar 36 is a mounting aperture 46 which is located between the first end of the bar and the mid-point between the first and second ends of the bar.

Each of the abrading members 12 receives in its respective mounting aperture 46 one of the cylindrical rods 48 shown in FIGS. 1-3 which are in the form of a headed bolt 50 having a nut 52. The diameter of the mounting aperture 46 is larger than the diameter of the rod 48 such that the abrading member can pivot about the longitudinal axis C of the rod 48, shown in FIG. 3.

As shown in FIG. 3, each of the abrading members 12 is secured in the slot 26 by means of rods 48 passing through the apertures 28 and 30 in the bars 22 and 24 and through the mounting aperture 46, with the entire abrading member being partially received in the slots 26 formed by the U-shaped guide elements 20. Preferably, the width of each slot 26 is just slightly larger than the width of each abrading member 12 so that the abrading member can easily pivot in the slot.

As shown in FIG. 3, the abrading member 12 is pivotally mounted about the longitudinal axis C of rod 48 in a position offset from the axis of rotation B of the mounting means 14. Additionally, the plane D which is perpendicular to the axis C, and is substantially parallel to the planar surface of the abrading member 12, forms a positive subtended angle of 60 with the plane A which is perpendicular to the axis of rotation B of the mounting means.

Additionally, as shown in FIG. 3 the dihedral angle E formed between the plane of the abrading edge 44 and the plane A perpendicular to the axis of rotation B is less than 180. This position shown in FIG. 3 is the rest position of the device, with the dihedral angles being in the configuration shown due to the relative positioning of the mounting apertures 46 and the centroids of each of the abrading members 12.

As shown in FIG. 1, the present invention can advantageously be connected to an electric drill 56 to provide the drive means for the mounting means 14. Specifically, the electric drill 56 has a chuck 58 which receives one end of the connecting element 18 in the form of a cylindrical bar. The other end of the connecting element can advantageously be a clevis 60, shown in FIG. 5, which is rigidly connected to the cylindrical body 16 via a bolt 62 passing through suitable apertures 64 and 66 diametrically provided in the cylindrical body 16. The bolt 62 is rigidly secured by a nut 68 with the clevis 60 conforming to the inside cylindrical bore of the cylindrical body 16 so that relative movement of the clevis and the cylindrical body about the axis of the bolt 62 is prevented.

In operation, on actuating the electric drill 66, the mounting means 14 will be rotated at speeds of 2000 to 3000 r.p.m. Due to this rotation about axis B and the pivotal mounting of each abrading member 12 to the mounting means 14, each abrading member will pivot from its rest position shown in FIG. 3 to a dynamic position shown in solid lines in FIG. 1. This pivotal motion is due to centrifical force acting on the abrading members. As shown in FIG. 1, the position of the tranverse mounting apertures 46 in each of the abrading members, taken together with the moments of inertia of each of the abrading members, causes each member to assume a position such that the abrading edge 44 is at a dihedral angle greater than the dihedral angle in the rest position. This is the position in which the abrading members will remain unless a force acts to remove them therefrom. Thus, when the abrading members 12 are placed against the surface 70 to be abraded, as shown in FIG. 1, and pressure is applied thereto the angle increases to that shown in phantom in FIG. 1, or even to a larger angle depending on the pressure exerted. In this position the rotating abrading members abrade surface 70.

Additionally, because the abrading members tend to stay in the position having a smaller angle, a chipping action will be provided to surface 70 each time one of the abrading members is forced upwards by a surface imperfection extending upwards therefrom. This oscillation of the abrading members enhances the abrading qualities of the device. Furthermore, since the abrading members are at an angle which is less than to the surface being abraded, there is less bending stress on the mounting means, the chips and dust abraded from the surface tends to be pushed away therefrom and the chipping action is enhanced due to the angle formed by the abrading members with the surface.

While the angle described above regarding FIG. 3 was designated as 60, it is contemplated that that angle can be as small as about 30 and can range upwards to about 60 for optimum results. However, in any event it has been found advantageous to have that angle as less than 90. In FIG. 6, the angle is shown as 30 and in FIG. 7 the angle is shown as 45.

While the abrading member 12 shown in FIG. 4 is substantially rectangular and has planar sides, it is also contemplated that the abrading member can be curved along its height from its top edge to the abrading edge. Thus, as shown in FIG. 8, an abrading member 72 is shown being curved along a portion of its height from the top edge 74 to its abrading edge 76. It is contemplated that the slight curve given to the abrading member 72 will increase the capacity of the abrading member to force away from the surface being abraded various chips and dust removed therefrom.

While the abrading member 12 shown in FIG. 4 has the mounting aperture 46 below the midline between the top edge 42 and the abrading edge 44, this is merely one manner of assuring that the abrading member will be positioned as shown in solid lines in FIG. 1 during rotation. That is, with the mounting aperture so positioned, the centroid of the abrading member will be above the midline between edges 42 and 44. However, the mounting aperture may be positioned along or above this midline is, for example, the abrading member itself were in the form of an inverted L-shaped bar or a T-shaped bar.

The direction of rotation of the mounting means 14, as shown in FIG. 2, is preferably clockwise, although the direction could be counter-clockwise if desired.

While certain advantageous embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. An abrading device adapted for use in combination with a rotating drive means, said device comprisat least two axially elongated abrading members,

each comprising a blade portion having a first end, a second end, a top edge and an abrading edge, and having mounting apertures, each aperture located in one of said blade portions between said first end and the midpoint between said first and second ends;

mounting means, rigidly connected to and rotatable by said rotating drive means, for supporting said abrading members,

said mounting means including means for freely supporting said abrading members for pivotal movement about fixed axes, at a position offset from the axis of rotation of said mounting means, said mounting means having an axis of rotation coaxial with the axis of rotation of said drive means,

said means for freely supporting said abrading members including rods secured to said mounting means along said axes, each of said axes being perpendicular to a plane which forms a positive subtended angle of less than with a plane perpendicular to said axis of rotation,

said mounting apertures each having a diameter larger than said rods and each of said rods passing through one of said apertures,

said means for freely supporting said abrading members also supporting said! abrading edges in noncoplanar planes when said drive means is not rotating, said edges forming dihedral angles of less than with a plane perpendicular to said axis of rotation,

said means for freely supporting said abrading members also supporting said abrading edges at an angle to the plane perpendicular to said axis of rotation which is greater than said dihedral angles when said rotating drive means is operated so said abrading edges describe a conical surface,

said device being operative to accomplish abrading by engaging at least a portion of said abrading edges against an object as said abrading members rotate to thus cause said .abrading edges to abrade said object.

2. An abrading device according to claim 1, wherein said angle is in the range of about 30 to about 60.

3. An abrading device according to claim 1, wherein said angle is about 60.

4. An abrading device according to claim 1, wherein said angle is about 45.

5. An abrading device according to claim 1, wherein said angle is about 30.

6. An abrading device according to claim 1, wherein each of said abrading members is rectangular in crosssection.

7. An abrading device according to claim 1, wherein at least one of said abrading members is curved along at least a portion of the distance from said top edge to said abrading edge. 

1. An abrading device adapted for use in combination with a rotating drive means, said device comprising: at least two axially elongated abrading members, each comprising a blade portion having a first end, a second end, a top edge and an abrading edge, and having mounting apertures, each aperture located in one of said blade portions between said first end and the midpoint between said first and second ends; mounting means, rigidly connected to and rotatable by said rotating drive means, for supporting said abrading members, said mounting means including means for freely supporting said abrading members for pivotal movement about fixed axes, at a position offset from the axis of rotation of said mounting means, said mounting means having an axis of rotation coaxial with the axis of rotation of said drive means, said means for freely supporting said abrading members including rods secured to said mounting means along said axes, each of said axes being perpendicular to a plane which forms a positive subtended angle of less than 90* with a plane perpendicular to said axis of rotation, said mounting apertures each having a diameter larger than said rods and each of said rods passing through one of said apertures, said means for freely supporting said abrading members also supporting said abrading edges in non-coplanar planes when said drive means is not rotating, said edges forming dihedral angles of less than 180* with a plane perpendicular to said axis of rotation, said means for freely supporting said abrading members also supporting said abrading edges at an angle to the plane perpendicular to said axis of rotation which is greater than said dihedral angles when said rotating drive means is operated so said abrading edges describe a conical surface, said device being operative to accomplish abrading by engaging at least a portion of said abrading edges against an object as said abrading members rotate to thus cause said abrading edges to abrade said object.
 2. An abrading device according to claim 1, wherein said angle is in the range of about 30* to about 60*.
 3. An abrading device according to claim 1, wherein said angle is about 60*.
 4. An abrading device according to claim 1, wherein said angle is about 45*.
 5. An abrading device according to claim 1, wherein said angle is about 30*.
 6. An abrading device according to claim 1, wherein each of said abrading members is rectangular in cross-section.
 7. An abrading device according to claim 1, wherein at least one of said abrading members is curved along at least a portion of the distance from said top edge to said abrading edge. 